|
 Australian
Bionic Eye Gives Hope to Blind
from Health World Online, August 29, 2002
For more articles on disabilities and special ed visit
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SYDNEY, Australia, Aug 29, 2002
(United Press International via COMTEX) -- Australian
researchers have announced they are developing a bionic eye
that could return some sense of sight to blind people with
hereditary degenerative diseases of the retina.
It is an advance that could do for the blind
what the cochlear implant has done for the profoundly deaf,
the researchers said.
The team, from the University of New South
Wales and the University of Newcastle, has been working on the
project since 1997. They said they are near to finding a way to
replace the function of the damaged part of the eye.
Project leader Nigel Lovell told United Press
International that trials of the device on sheep have evoked
brainwaves consistent with vision.
"It shows we're heading in the right
direction," he said.
The retina consists of a layer of
light-sensitive nerve cells on the back of the eyeball. In a
normal functional eye, a spot of light cast upon the retina
triggers what the scientists call a "cascade of physiological
events." This culminates in an electrochemical signal that
spreads from retinal nerve cells, traveling along the optic
nerve to the vision centers of the brain for interpretation.
In a diseased eye, the cascade no longer
occurs, so there is no electrochemical signal to the brain.
Researchers have found the electrochemical
signal can be initiated by delivering an electronic pulse to the
appropriate nerve cells. That is what the bionic eye would do.
It would replace the eye lens with a capsule
the size of a dime holding a microchip linked by platinum wires
to the retina. The chip would receive pictures radioed from a
tiny camera attached to a pair of glasses. Signals reaching the
retina would produce 100 points of light, 10 rows wide and 10
columns deep, creating a pixilated image like those shown on
television reports where a person's identity needs to be
concealed.
"Down the road, it sounds pretty exciting,"
Robyn Richards, president of Retina Australia, told UPI. "I
don't want people to get false hope, but the bionic eye could
one day make a big difference to totally blind people."
Retina Australia is a voluntary organization
that provides scientific research and support to people and
families affected by retinal degenerative diseases.
An estimated 10 million Americans suffer from
blinding eye diseases, such as macular degeneration and
retinitis pigmentosa. The degeneration is gradual, typically
starting with night blindness, then progressing to tunnel vision
and then complete blindness.
People with the affliction also suffer
sleeping disorders due to their inability to discern light from
dark. To date, there is no cure or treatment.
In the United States, a parallel effort has
been under way to develop an artificial vision system. Led by
ophthalmologist Alan Chow of Chicago, it involves implanting a
computer chip into the retina.
Lovell is keen to distance himself from the
American device, however.
"The big difference is that in our bionic eye,
the camera is outside the body," he said. "We don't believe Dr.
Chow's invention will work because it is not bio-compatible. The
body is a corrosive place and the electronics won't survive
long. What's more, once the device inside the eye, if there are
any problems, it will be impossible to extract it safely."
Lovell said the bionic eye will not restore
perfect vision but could improve a patient's quality of life. As
a start, he said, it would allow patients to discern night from
day, probably relieving them of sleeping disorders.
In addition, patients might be able to detect
movement and objects, which would help them get around without
bumping into things. It might even be possible to read very
large print in some cases.
It will be some time -- perhaps 5 years --
before the bionic eye will be commercially available, Lovell
said. The next step is to test the device by implanting
electrodes inside a person's eye for a day or so and recording
what happens.
Lovell relates development of the device to
cochlear implants. The first devices were not that successful,
he said, and it was 20 years before Cochlear Ltd., a Sydney
company, was able to put the device inside the human body.
The cochlear implants remain controversial.
Last month, the U.S. Food and Drug Administration reported at
least 25 cases of bacterial meningitis had been diagnosed
worldwide among patients with the ear implants.
Richards, who has been legally blind since she
was 38 -- after being diagnosed with retinitis pigmentosa at 33
-- said she hopes the research bears fruit.
"It will be great when it comes," she said,
"but it would be dangerous for people like myself to get our
hopes up too much at this stage." | 